Table of Contents
Advertisement
Troubleshooting
●
Temperature Abnormality
NOTE : Temperature monitor operation
===
The temperature monitor system is provided to prevents damage of optical components (the
LCD panel and polarization film etc.) inside a projector from overheat. Two protection systems
are provided.
Each system operation as follows :
The temperature monitor -1:
------
■
To control the air-flow of the cooling fans.
The CPU checks the temperature and atmospheric pressure inside a projector. It checks tem-
perature using temperature sensor-IC5801,IC1519 and it checks an atmospheric pressure
using pressure sensor-IC4849.
CPU judges data from sensors and controls the air flow of the cooling fans so the temperature
inside a projector is maintained to normal temperature.
■
To shut down the projector urgent.
The CPU checks temperature of inhalation air(IC5801). If this part temperature reaches to abnor-
mal temperature, the CPU will turn off a projector, and will blink WARNING TEMP. indicator at
intervals of 0.6 seconds. Cooling fans operate until temperature returns to normal. Indicator will
Hot circuit
FUSE
F901
AC-INPUT
CHECK Fan
RECTIFIER
LAMP NET
NOTE : WARNING TEMP. LED OPERATION
■ The red LED indicates temperature monitor operation as fol-
lows:
LED off:
Normal temperature.
LED flashes :
Abnormality temperature.
Doesn't the WARNING TEMP.
indicator (red) blink?
The projector is turned off when
the temperature around the LCD
panel reaches abnormal temper-
ature. And a WARNING TEMP.
indicator blinks.
========================
------------------------------------------------------------------
INTERLOCK SW
SW902
FANS
FANS
CHECK !
AMP.
COMPARATOR
REF. VOLTAGE
LAMP
REPLACE
WARNING
TEMP.
READY
LAMP
INDICATORS
stop blink, if temperature returns to normal. Trace the cause of the abnormalities-temperature,
and repair the projector.
The temperature monitor -2 :
------
■
Temperature check of lamps :
Thermal switches are arranged near the lamps. Thermal switches will operate, if temperature
reaches 95 - 100 degrees. When temperature switches have operated, PFC units will be shut
down, then a projector will be turned off.
■
Note :
(1) Usually temperature monitor-2 will operate when other protection equipment did not operate
with trouble, so it is auxiliary protection equipment. When other protection equipment is right-
ly operating, this temperature monitor-2 rarely operates. If this temperature monitor-2 has
operated it is thought fault of other protection equipment.
(2) The CPU does not check operation of thermal switches. Therefore, when thermal switches
have operated and a projector has shut down, WARNING TEMP. indicator does not blink.
CURRENT SENSOR
ASS'Y POWER
A903
DC out
16V /9V /6.35V /-6V
POWER
CONTROL
FAN
ON/OFF
CONTROL
I / O
EXPANDER
A901
SUB POWER
CHECK !
IC801_234
NOTE : CPU OPERATION
■ The CPU (IC801) performs an input check by the IIC-
SDA signal pin.
■ When it has detected abnormal condition, the CPU
turns off the projector compulsorily. Cooling fans oper-
ate until temperature returns to normal. Moreover, a
projector cannot be turned on during this period.
-66-
------------------------------------------------------------------
SWITCHING
A902
POWER SUPPLY
DC out 25V
Always
DC out
SWITCH
Switched
CPU IC801
and
I / O
EXPANDER
IC4801
Advertisement
Table of Contents
